Galvanizing apparatus



- P -7; H. w. BRADLEY 2,328,949

GALVANI Z ING APPARATUS Filed. April 26, 1940' 2 Sheets-Sheet 1 P 1943'. H. w. BRADLEY 2,328,949

GALVANI Z ING APPARATUS Filed April 26, 1940 2 Sheets-Sh eet 2A Ewam Patented Sept. 7, 1943 orrica GALVANXZING APPARATUS Howard W. Bradley, Calumet City, Ill., assignor r. to Inland Steel Company, Chicago, 111., a corporation ofDelaware Application April 26, 1940, Serial No. 331,861

Claims. (Cl. 91-125) My invention relates generally to apparatus for coating articles, such as for example, metal sheets, with molten metal applied thereto from a molten metal bath through which the articles are passed, and comprising stratified molten metal layers of metal of different specific weights.

An instance of such an apparatus is that used in the well known hot-dipgalvanizing process wherein the molten metal bath through which the articles are passed for galvanizing them, is composed of lead and zinc, the lead, becauseof its high specific weight, underlying the zinc. In such a bath lead oxides and other matter lighter than lead, but, heavier than zinc, tend to float on the lead surface at the interface between the lead and the zinc, likewise zinc-iron compounds and a other matter heavier than zinc, but lighter than lead, tend to drop to thinterface and float onthe lead; thereb causing a layer of dross to accumulate at the interface.

Such a condition is very objectionable particulariy in the practice of galvanizing sheet metal, inasmuch as particles of this accumulated dross, through which the articles being galvanized pass,

cling to the surfaces of the articles resulting in I the apparatus being broken away to disclose an otherwise obscured detail of the construction; and

Figure 2, a section taken at the line 2 on Fig. l and viewed in the direction of the arrow.

The apparatus shown and which as to its general features of construction, is of a well known form, c'omprises a receptacle, or pot, 3 for the molten metal bath composed of a lower layer 4 of molten lead and a superposed layer 5 of molten zinc, the interface between these layers and at which dross accumulates as above described and diagrammaticall represented at 6 of the dross at a portion only of the interface, being indicated at I.

Platelike supports 8, spaced apart, seat at their ends on the upper edge of the receptacle 3 and extend into the latter and intothe metal bath, to a point closely adjacent the bottom of the receptacle. I

The plates 8 form supports for means whereby the sheets to be galvanized and fed into the receptacle through its top at one end are caused to pas through the bath and discharge through the top of the receptacle at its opposite end; these means comprising spacedapart bar 9 supported by cross rods l0 secured to the supports 8 and'formin a curved openwork guideway submerged in the bath and presenting a curved guide channel H for the sheets.

'At the upper flared inlet end I 2 of the guideway and at its lower central portion and'at its exit end 13, are sets [4, l5 and IE, respectively, of rolls forming sheet feeding means which operate to feed the sheets to be coated downwardly, in the direction of the arrow. in Fig. 2, through the guide channel- II and through the bath and thence out through the discharge end l3 of the guide channel; these roll means being operated in any desirable way as for example in accordance with common practice.

In accordance with my invention I provide for the isolating of the dross 6 at the interface I,

. throughout substantially the full extent of such interface, from contact with the sheets as they move upwardl through the discharge end por-,

tion of the guideway; and to this end I provide an imperforate shield represented at I l and shown as of general boxlike form having a surrounding -wall l8 open at its upper and lower ends; the shield being shown as supported by rods I9 spaced apart and secured to the platelike members 8.

The shield I l surrounds the guide for the sheets adjacent the outlet end of the latter and extends to points above and below the interface I, preferably extending a considerable distance below the interface and conforming in contour to the guideway as shown, thus being of curved shape.

The outerwall of the shield extends downwardly preferably to the position shown at 20 in which it projects across the lower edge 2| of the opposite wall of the shield, thus minimizing the rise of dross in the molten lead 4 into the shield l'I.

-While the sheet in moving outwardly in the guideway passes through the interface between the lead and zinc, within the shield, the effect of the dross onthe sheets is negligible within the small area within the shield as such accumulations of dross as may occur therein and which is minimized by shaping the shield as above stated, are rapidly cleared by the passage of the do not wish to be understood as intending to limit it thereto as the same may be variously modified and altered and the invention embodied in other forms of structure without de-' parting from the spirit of the invention.

What I claim as new and desire to secure by Letters Patent is:

1. In a metal-coating apparatus, incombination, a receptacle for a molten bath comprising metals of different specific weights one superposed on the other thereof and through which the article to be coated is passed, the interface between said metals at which dross accumulates being substantially coextensive with said bath, and shielding means for the article positioned to extend in such layer of dross as may occurat the interface between said metals, crosswise of such layer throughout the height of such layer and to a plane below the upper surface of the lighter metal, adjacent the exit of the article from the bath, for shielding the article from contact with dross exterior of the shielding means.

. 2. In a metal-coating apparatus, in combination, a receptacle for a molten bath comprising metals of different specific weights one superposed on the other thereof and through which the article to be coated is passed, and shielding means for the article positioned to extend in such layer of dross as may occur at the interface between said metals, crosswise of such layer throughout the height of such layer and to a planebelow the upper surface of the lighter metal, adjacent the exit of the article from the bath for shielding the article from contact with dross exterior of the shielding means, one of the walls of the shielding means extending at its lower end into the metal of greater specific weight into a position adjacent the vertical plane in which the lower edge of the opposite wall of the shielding means extends -to minimize rise of dross from the body of the bath into said shielding means.

3. In a metal-coating apparatus, in combination, a, receptacle for a molten bath comprising metals of different specific weights one superposed on the other thereof and through which .the article to be coated is passed, an articleguiding and article-shielding means removable from, and replaceable in, the bath as a unit, said-article-shielding means positioned to extend in such layer of dross as may occur at the interface between said metals, crosswise of such layer throughout the height of such layer and to a plane below the upper surface of the lighter metal, adjacent the exit of the article from the bath, for shielding the article from contact with dross exterior of the shielding-means.

4. In a metal coating apparatus, in combination, a receptacle for a molten bath comprising metals of different specific weights one superposed on the other and through which the article to be coated is passed, the interface between said metals being substantially coextensive with the bath, shielding means for the article comprising side and end walls constituting a closed structure, and means supporting said shielding means with said walls extending throu h the interfac'e between said metals and any layer of dross thereat and to a plane below the upper surface of the lighter metal, and above and below said interface, about'the path of the article adjacent its exit from the bath.-

5. In a metal coating apparatus, in combination, a receptacle for a molten bath comprising metals of different specific weights one superposed upon the other at least substantially throughout the bath and through which the article to be coated is to be passed, spaced substantially parallel support members-formed with portions to overlie and rest upon edges of the receptacle and portions to be submerged in the lower of said metals, rod members extending between and secured to said support members, article guiding members secured to said rod members toguide the article to be coated into'and out of submergence in each of the metals, and shield means secured between said support members at the 'exit end of said guide members positioned to project above and below the interface between said metals and any layer of dross thereat to protect the article to be coated from contact with any substantial amount of dross.

HOWARD W. BRADLEY. 

